Photocatalytic decomposition of insecticides in the suspension reactor

Neonikotinoidi su nova grupa insekticida koji su potisnuli iz uporabe stare insekticide (organofosfate i metilkarbamate), a u novije vrijeme izazivaju sve veće onečišćenje okoliša. U ovom radu provedena je fotokatalitička razgradnja imidakloprida kao glavnog predstavnika neonikotinoidnih insekticida. Cilj ovog rada bio je ispitati fotokatalitičku razgradnju imidakloprida primjenom TiO2 fotokatalizatora u suspendiranom obliku. Fotokatalitički eksperimenti provedeni su u anularnom fotokatalitičkom reaktoru s recirkulacijom reakcijske smjese. U unutrašnjoj cijevi anularnog reaktora bio je smješten odgovarajući izvor zračenja(Arcadia natural sunlight lampa, UV-A i UV-C lampa). Reakcija je provedena pri različitim radnim uvjetima (pH, valna duljina zračenja, koncentracija katalizatora). Istraživanje je uključivalo primjenu komercijalnog titanijevog dioksida (TiO2 P25; Degussa/Evonik), komercijalnog TiO2 P25 izloženog djelovanju UVC zračenja prije provedbe fotokatalitičke razgradnje i dušikom dopiranom TiO2 (proizvedenom u Cinkarni Celje). Reakcija je praćena primjenom tekućinske kromatografije visoke djelotvornosti. Također je provedena analiza ukupnog organskog ugljika. Nađeno je da imidakloprid apsorbira zračenje u UV području spektra, te da porastom masene koncentracije fotokatalizatora (0,05 do 0,5 g/L) raste brzina fotokatalitičke razgradnje imidakloprida.Neonicotinoids are a new group of insecticides that have been suppressed by the use of old insecticides (organophosphates and methylcarbamates), and have been increasingly polluted by environmental contamination. In this work, photocatalytic degradation of imidacloprid as the principal representative of neonicotinoid insecticides was carried out. The aim of this work was to examine the photocatalytic degradation of imidacloprid by using a TiO2 photocatalyst in suspended form. Photocatalytic experiments were performed in an annular photocatalytic reactor with recirculation of the reaction mixture. In the inner tube of the annular reactor was located the appropriate radiation source (Arcadia natural sunlight lamp, UV-A and UV-C lamp). The reaction was carried out under different working conditions (pH, wave length, concentration of catalyst). The research involved the use of commercial titanium dioxide (TiO2 P25, Degussa/Evonik), commercial TiO2 P25 exposed to UVC radiation before photocatalytic degradation and nitrogen-doped TiO2 (produced in Cinkarni Celje). The reaction was monitored by the application of high performance liquid chromatography. An analysis of total organic carbon was also carried out. Imidacloprid has been found to absorb radiation in the UV spectrum, and the increase in photocatalytic degradation rate of imidacloprid increases with the increase in photocatalyst concentrations (0.05 to 0.5 g/L)